<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>vue-test</title>
    <script src="https://cdn.bootcss.com/vue/2.5.8/vue.js"></script>
    <script src="https://cdn.bootcss.com/vuex/3.0.0/vuex.js"></script>

</head>

<body>
    <div id="firstVue">
        {{count}}
    </div>
    <script>
            var app=new Vue({
                el: '#firstVue',
                // state
                data:{   
                    count: 0
                },
            
                methods: {
                    increment() {
                        this.count++
                    }
                }
            })
        </script>
</body>

</html>